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Technology workshop: Out-of-autoclave solutions for advanced composites

Workshop background

Depending on the context, the mechanical properties of structural composite applications can vary widely. The following cases are just a sample of this variability. Boat hulls require stiffness and resistance to impact loading; underground storage tanks are designed to resist relatively static loads; and aerospace composites must have very low weight and very high modulus – the opportunity and a challenge for composite materials.
The hallmark of advanced composites is to provide maximum tensile and compressive properties – per specific weight. There are three major characteristics that influence the development of advanced composite properties: fibre modulus (tensile), fibre volume fraction and laminate void content.
Because the void content and fibre volume fraction are so important to the performance of advanced composites, autoclave processing has been the standard method to optimize specific strength. Developments in Out-of-Autoclave (OOA) processing focus on not only eliminating es the expense of autoclaving, but also reduces tooling costs.

Workshop objectives
At the completion of this workshop participants will be able to:

  • Understand the three major characteristics that influence the development of advanced composites properties;
  • Identify those characteristics required in specific applications / products / industries;
  • Understand the general principles of autoclave processing,; and the real cost and the practical barriers inherent the system;
  • Articulate the advantages and limitations of emerging OOA processes;
  • Understand how these OOA processes can positively impact on the sustainable growth of advanced composites – in both aerospace and non-aerospace applications.

Workshop outline
If autoclaves are eliminated from the equation, composites processing becomes much more cost-effective and accessible. The aerospace industry can maintain significant performance at much reduced cost, whereas the general composites industry can move toward opportunities in the advanced composites through employing OOA processing methods. This workshop will cover:

  1. Discussion of the inherent mechanical properties required for various types of composites applications
  2. Differences between aerospace and commercial composites
  3. Properties that have a greater influence on advanced composites – Modulus, FVF, Void content
  4. Advantages of autoclave prepreg curing
  5. But what happens when the aerospace products become is cost driven rather than performance driven – the problem with the autoclave process
  6. Examining Vacuum-Bag Only (VBO) oven-cured prepregs
  7. Where Vacuum Infusion Processing (VIP) is filling the gap
  8. Fundamental advantages of the infusion process
  9. Tooling-centric RTM vs. basic tooling for VIP
  10. Variations on the theme.

In addition, the worksheet will focus on:

  • Materials
    • Specific comparisons of traditional carbon fibre properties in autoclave processing and the potential for minor changes in laminate design to facilitate OOA processing.
    • The principles of fibre reinforcement and fundamental carbon fibre performance criteria
  • Processes
    • Transitioning from open moulding to VIP or VBO to move toward more sophisticated markets.
    • The gap between commercial glass fibre fabrication and more sophisticated carbon fibre applications is considerably narrowed if one has mastered the VIP process.

Target audience

The workshop is intended for production, technical and management personnel of composites companies, or those looking to develop advanced composites capabilities.
In addition, engineering and technical practitioners and students responsible for specifying and designing structures likely to benefit from use of advanced composites will find these seminars extremely informative.

About the presenter, Bob Lacovara